SDCard doesn’t support hot plug and play. You can reboot your device to see if there is there.
/dev/sdb is not a partition. The correct partition should be /dev/sdb1, with a number at the end. It seems that the system cannot find the correct partition.

From the log you posted at the first post, it seems to recognised the correct device. You USB device is 32G? Can you use a 4G or 8G one to try?